One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,19)(12,16)(13,17)(14,18)(15,21)(20,24)(22,23)(25,26,30,33)(27,31,34,38)(28,35,37,40)(29,36,39,32)(1,2,4,5)(3,7,8,6)(9,11,14,21)(10,15,18,19)(12,20,13,22)(16,23,17,24)(25,27,30,34)(26,31,33,38)(28,36,37,32)(29,35,39,40)(2,5)(6,7)(9,12,14,13)(10,16,18,17)(11,20,21,22)(15,23,19,24)(25,28,29,38,30,37,39,31)(26,27,32,35,33,34,36,40)(9,12,14,13)(10,17,18,16)(11,20,21,22)(15,24,19,23)(27,34)(28,37)(31,38)(35,40)(1,3,4,8)(2,6,5,7)(9,13,14,12)(10,17,18,16)(11,20,21,22)(15,23,19,24)(27,34)(28,37)(31,38)(35,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.